The study by Choi et al. (2007) with the opposite effect was performed with much larger particles (_50 lm), and the impact of the particles was actually quite small.
Further, Motwani et al. (2011) stated that the interfaces of particles could be covered with liquid oil and thereby oil migration increases. Additionally, they suggested that the non-fat particles do not support the growth of fat crystal clusters leading to a more heterogeneous crystal network possibly resulting in higher permeability and enhanced migration of oil.